| 摘要 |
<p>1533942 Optical transmission system ROBERT BOSCH GmbH 29 June 1977 [1 July 1976] 27184/77 Heading G1A A signal is transmitted along a glass fibre using pulse frequency modulation of the optical signal. A second signal may be transmitted in multiplex using pulse duration modulation. The signal is fed to voltage controlled oscillator 2, the output of which is shaped by monostable 3, amplified (4) and used to modulate laser or LED 5 feeding the glass fibre 6. The signal detected (7) at the other end of the fibre is amplified (16), limited (17), shaped (8) and low pass filtered 9. The second signal 18, if present, modulates the monostable duration. This signal is detected after limiting by circuit 11 which passes current from source 20 to capacitor 19 during each pulse, stores the peak values at 12 and discharges the capacitor between pulses.</p> |
